The supply chain for lumber used to build houses begins with growing timber which is cut into logs and delivered to a lumber mill. The logs are delivered to the sawmill portion of the lumber mill. Modern sawmills are highly automated and cut each log into various dimension lumber, or board, sizes that produce the most useful dimension lumber possible from the logs. The output of the sawmill portion of a lumber mill is a mix of lumber sizes which are routed to sorting machines that separate the lumber into bins for each size, e.g. ten foot long 2×4s (two by fours), twelve foot long 2×6s, etc. The sawmill sorting operation normally does not sort by grade.
The separated lumber from the sawmill is typically dried and then delivered to the planermill portion of the lumber mill. In the planermill, the lumber is planed, graded, and sorted again according to grade as well as dimensions before being packaged in pallet loads, e.g. full pallets of 208 ten-foot 2×4s, ready for sale.
The full pallets of lumber are typically sold to lumberyards. The lumberyards may resell full pallets. However, builders prefer that lumber be delivered to a building site with only the specific number of each size and grade of lumber needed for building a home. Some builders use computer systems for designing homes and the computer systems often generate one or more bills of materials or material take off lists for the specific home. One typical bill of materials lists all of the lumber needed to frame a house. If the builder has such a computer-generated bill of materials, he typically provides the bill of materials to a lumberyard. A yard worker uses the list to collect the specified numbers of each lumber dimension and grade, assemble the collected lumber into manageable bundles, and strap the bundles for delivery by truck to a building site. If a builder does not have a computer-generated bill of materials, he may simply provide a house plan to a lumberyard and the yard worker may produce a bill of materials from the plan. The lumber for framing a house is typically called a framing package or frame pack, although it typically includes a number of separate bundles or subpackages.